Pressurized Packaging Systems for One Component Adhesives and Sealants

ABSTRACT

A pressurized container for dispensing a 1K adhesive or sealant composition is disclosed. The container has an outer container with at least one dispensing opening and a deformable inner container to be filled with the 1K composition. The inner container is accommodated in the outer container and also has a dispensing opening. The inner container is connected to the outer container. The outer container has a pressure generator containing an amount of activated carbon having a propellant gas adsorbed thereon.

FIELD OF THE INVENTION

The present invention relates to pressurized packaging systems for one component (1K) viscous products, in particular adhesives and sealants.

BACKGROUND OF THE INVENTION

Advanced packaging design and technology is the key to manufacturing pressurized packages that ensure the maximum efficiency and effectiveness of dispensing fluida.

Pressurized packaging designed for effectively and efficient dispensing viscous reactive products such as adhesives and sealants are complex. The requirements, hence specifications, for such pressurized packaging components or parts in said applications require special conditions or equipment.

Generally pressurized container-dispenser devices use compressed gases, such as hydrocarbons, that are charged to a container containing a bag of a fluid whereby actuation of a valve provided in the can causes the gas to press on the bag and force the ingredient out from the container. However, discharge of the fluid tends to tail off as the pressure in the container falls resulting in non-uniform and inefficient dispensing of the fluid. Furthermore, the use of hydrocarbons that are volatile organic compounds is environmentally unfriendly.

Accordingly, it is an object of the present invention to provide an improved method for storing and dispensing viscous 1K adhesive and sealant compositions that, amongst other benefits and advantages, enables a greater volume of composition to be stored and dispensed in a given volume.

A further object of the present invention is to provide a method of discharging viscous 1K adhesive and sealant compositions from a storage container that does not require the use of volatile organic compounds and allows a more uniform and efficient discharge of the viscous 1K adhesive and sealant compositions.

In accordance with the present invention, it has now been found that the above-described specifications can be fulfilled. The present invention provides for cost efficient and effective storing and dispensing of the reactive viscous adhesive and/or sealant compositions as well as specifications and properties of the dispensing system itself.

Accordingly, the present invention provides a method of storing and dispensing at least viscous 1K adhesive and sealant compositions.

A second aspect of the present invention provides for a storage and dispensing container for viscous 1K adhesive and sealant compositions, the container comprising a pressure generator containing an amount of activated carbon having a propellant gas adsorbed thereon.

SUMMARY OF THE INVENTION

The present invention is directed to a pressurized container for dispensing a 1K composition, said container comprising an outer container having at least one dispensing opening, and a deformable inner container, potentially multi-compartment inner container, to be filled with the 1K composition said inner container accommodated in the outer container and which likewise has a dispensing opening and is connected to the outer container, further characterized in that the container comprises a pressure generator containing an amount of activated carbon having a propellant gas adsorbed thereon.

DETAILED DESCRIPTION OF THE INVENTION

As illustrated in FIG. 1, the present invention is directed to a pressurized container for dispensing a 1K composition, said container comprising an outer container (10) having at least one dispensing opening, and a deformable inner container (11) to be filled with the 1K composition said inner container accommodated in the outer container and which likewise has a dispensing opening and is connected to the outer container, further characterized in that the container comprising a pressure generator (12) containing an amount of activated carbon having a propellant gas adsorbed thereon.

The pressure generator is adapted to contain carbon material at a given pressure. Carbon material comprises an activated carbon that is charged with a propellant. The carbon can be charged by introducing a compressed gas or adding solid carbon dioxide to the pressure generator. The propellant will “charge” the adsorbent to an effective pressure for desired application and depending upon the amounts and ratio of carbon to propellant.

The pressure generator (14) in FIG. 2 is placed within the outer container 10 and has means to allow for the release of gas from carbon material. For instance, the release may comprise a valve (15) and connects to an actuator. The valve is utilized to charge the carbon with a gas, or a solid form of the propellant may be introduced into the can (containing the carbon). The propellant is carbon dioxide or a combination therewith. In examples, the propellant selected is carbon dioxide combined with dried ice. The carbon dioxide can be introduces either as a gas or a solid. Preferably solid carbon dioxide and/or dry ice was used to provide the adsorbed carbon dioxide

The activated carbon can be in a variety of forms, most commonly as powdered, granular or pelleted products. In addition, these forms come in a variety of sizes, which can affect the adsorption kinetics of the activated carbon. The base carbon, the activation process and the activated carbons' final form and size can all influence the material's adsorption performance.

According to the invention, the outer container contains carbon material in the lower part, such as it is shown at the bottom of the container in FIG. 1. The container 10 is adaptable for containing the carbon material at a range of pressures. The specific pressure generally depends upon the characteristics of the product such as its viscosity or density of the adhesive and/or sealant composition and what the customer appreciates in a practical or aesthetic sense-it could be higher or lower pressure on discharge or a bigger or smaller flow, for example. The specific pressure is determined by using a weight combination of carbon and gas carbon dioxide that will yield a generally consistent discharge rate. A pressure gauge can be used to measure the actual pressure of container 10. The final pressure obtained on discharge of the container should be not too much less than the initial pressure. In most instances the pressure drop, should not exceed about 2 bar and in some instances less than about 1 bar is desired.

Tests were conducted to determine appropriate pressures for container 10 as a function of the proportion of contents discharged for both a container having activated carbon material according to aspects of the invention, and a container having only compressed gas

In an example of the present invention, the container is designed to have a shape and size appropriate to accommodate a suitable pressure level for the select application. For example, the container may be packed with gas-loaded carbon to the maximum safety pressure limits dictated by the various regulations in force (for example, the European Transport Regulations). These limits may also be dictated by the design pressure of the container. When it is desired that the container contain relatively low pressures (compared to that for compressed gas without carbon), the container can be made from plastic material, for example, and molded into a square or rectangular or other convenient shape for efficient packing and transportation in bulk.

In an example, the same (maximum) pressure is used in the container whether it was adsorbed gas according to aspects of the invention. The higher volume of gas obtainable from the adsorbed gas would enable use of a lower pressure. This would still produce more volume released than for the compressed gas. Thus, for a given pressure there is more gas volume from adsorbed gas than from compressed gas alone. The lower pressure enable use of a plastic container such as PET or PP.

The container 10 can be designed to resemble that of a standard aerosol-type can and is preferably fabricated from PET. It can be of various sizes, shapes or designs. It can comprise bag-on-valve, bag-in-can or piston-operated devices. For example, container 10 provides a replacement for hydrocarbon propellants in the following way: the adhesive and/or sealant composition is enclosed inside a suitable PET/PP bag and gas adsorbed on the activated carbon is used to effectively squeeze the bag, or operate a piston, thereby dispensing the composition. The composition is stored in separate from the carbon material.

A container for a 1K adhesive or sealant composition for dispensing comprises a relatively stiff outer container having a dispensing opening. In the shown example outer container is manufactured from a hard plastic type such as PET. Container (10) further comprises a deformable inner container (11) which is accommodated in outer container and in which the product is ultimately received. This inner container, which is preferably manufactured from PET, is likewise provided with a dispensing opening and is connected in any case at the position of dispensing openings to the outer container. In one example the inner container is formed integrally with outer container so that it is connected over its whole surface to outer container. Inner container 4 and outer container 2 are formed here by injection molding.

According to one aspect of the invention, inner container is connected to outer container at a location remote from dispensing opening. For example there can be chemically connection by gluing or a mechanical connection, more particularly a snap or clamp connection, and the connecting location lies diametrically opposite dispensing openings of the outer and inner container. A dosing head i.e. aerosol valve (13) can be mounted on the neck around dispensing opening of the outer container. When inner container and outer container are formed separately, it is also relatively simple to arrange extra layers therebetween. These intermediate layers can likewise be formed by injection moulding and take a form corresponding to that of inner container and outer container. Intermediate layers can also serve as reinforcement for inner container or for the purpose of improving the chemical resistance. Whether the use of intermediate layers is necessary, and which materials must be used for this purpose depend on the nature of the product to be dispensed.

One-Component Adhesives and/or Sealants

“One-component adhesives” are to be understood, in particular, as those adhesives that cure by means of a change in environmental conditions. This can occur, for example, as a result of temperature elevation, entry of atmospheric humidity, exclusion of atmospheric oxygen, or contact with the substrate surface. The hardener component deriving from the environment, for example the water in atmospheric humidity, thus does not result in categorization as a two-component adhesive. One-component adhesives can therefore also contain multiple components already mixed with one another, which are stable under storage conditions and cure only upon application as a result of a change in environmental conditions. This can include, for example, reactive resin components or binder components such as, for example, polyols (e.g. Acclaim 2200N of the Bayer company, Leverkusen). One-component adhesives are generally usable by the consumer without the admixture of additional components such as, for example, hardeners. The one-component adhesives therefore also include, for example, compositions that contain silyl-terminated polymers and polyol or are made up of polyurethane prepolymers, since it is only the entry of atmospheric humidity that causes them to cure.

Examples of polyurethane prepolymers in one-component adhesives are known, for example from WO 03/066700; polymers that moisture-crosslink via silyl groups are known, for example, from U.S. Pat. No. 3,971,751, EP 1093482 A1, U.S. Pat. No. 7,009,022 B2, U.S. Pat. No. 6,756,465 B1, DE 10152505 A1, and DE 10350481 A1

EXAMPLE 1

In an embodiment of the present invention, a container filled with activated carbon/CO2 and fitted with a gap-failing, industrial sealant was tested to demonstrate effective product dispensation from a ‘bag-in-can’ system. The can volume was nominally 330 cm<3> and contained about 222 cm<3> (270 g) of the sealant held in an integrated bag-in-can system.

The carbon material was prepared by first calculating appropriate weights of granular activated carbon and solid carbon dioxide needed to produce a full can pressure of 7 bara and a fully discharged can pressure of 5 bara.

The dispensation of sealant through the top valve fitment was considered as successful with a steady, even and manageable flow of the product throughout the dispensation. An effectively complete discharge of sealant was achieved. On destructive opening of the can it was observed that the sealant bag was completely discharged.

EXAMPLE 2

A commercial, viscous sealant comprising trimethoxyvinyl silane and contained in a can of approximately 150 cm<3>.

According to aspects of the invention, the propellant chamber 1 was carbon material comprised of calculated quantities of activated carbon and solid carbon dioxide and dry ice. The quantities of activated carbon and carbon dioxide were calculated as to give a starting pressure in the region of 6-7 bara and a final pressure on full discharge of 5 bara (pressures measured at 25 [deg.] C.)). The resulting container was noted to give a complete discharge of the product with a very satisfactory and controlled flow rate. 

1. A pressurized container for dispensing a 1K adhesive or sealant composition, said container comprising an outer container having at least one dispensing opening, and a deformable inner container to be filled with the 1K composition said inner container accommodated in the outer container and which likewise has a dispensing opening and is connected to the outer container, the outer container comprises a pressure generator containing an amount of activated carbon having a propellant gas adsorbed thereon.
 2. The pressurized container according to claim 1 wherein the propellant gas is carbon dioxide combined with dried ice.
 3. The pressurized container according to claim 2 wherein the outer and inner container is fabricated from PET.
 4. The pressurized container according to claim 3 wherein the inner container is connected to outer container at a location remote from dispensing opening.
 5. The pressurized container according to claim 4 wherein the connection is made by gluing.
 6. The pressurized container according to claim 1 wherein the outer and inner container is fabricated from PET.
 7. The pressurized container according to claim 1 wherein the inner container is connected to outer container at a location remote from dispensing opening.
 8. The pressurized container according to claim 2 wherein the inner container is connected to outer container at a location remote from dispensing opening.
 9. The pressurized container according to claim 1 wherein the connection is made by gluing.
 10. The pressurized container according to claim 2 wherein the connection is made by gluing.
 11. The pressurized container according to claim 3 wherein the connection is made by gluing. 